Water-soluble package and method for making and using same



United States Patent 3,277,009 WATER-SOLUBLE PACKAGE AND METHOD FOR MAKING AND USING SAME Milton Freifeld, Easton, and Willis G. Thomas, Jr., Bethlehem, Pa., assignors to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 3, 1961, Ser. No. 142,525

18 Claims. (Cl. 252-90) This invention relates to a method of treating and/or handling solids and liquids intended to be dispersed in the form of a suspension, emulsion or solution in an aqueous medium and in particular to a method for packaging such solids and liquids and to the resultant treated solids and liquids and packages.

In very recent years the packaging of detergents in plastic envelopes or packages which are soluble in the wash water has become a very important adjunct of the packaging art. The advantages of such a package are manifest. Predetermined and pre-elected amounts of material can be added to the laundry bath which makes for a cleaner and altogether more desirable operation. Obviously there are many problems which must be solved to find the best package. The latter must of course be formed of a water-soluble material, again obviously this leaves for practical consideration only water-soluble polymers.

Many come to mind as being potentially V useful but all which have heretofore been proposed suffer from at least one or more deficiencies measured by their failure to meet the standards hereinafter to be described.

In order to find utility as a coating or in the packag' ing of solids and liquids, a water-soluble polymer must have certain properties. It must be capable of forming a continuous, homogeneous fim. Its solubility in water must be great enough to permit reasonable concentration of polymer in solution. Its rate of solution in water, both cold and hot, should be rapid. Its rate of solution and solubility in water should not be materially affected by the pH of the water. It should exhibit good stability on aging. Films or coatings formed from the polymer must have adequate physical strength to withstand manufacturing procedures and normal handling and use abuses. They must have low tack and show only minor blocking tendencies. They must be able to withstand low and high humidity conditions without major loss of physical strength. They must be able to Withstand low and moderately high temperature without loss of requisite properties. They must not be attacked and in turn must not attack the materials which they envelop or contain.

It is therefore an object of the present invention to provide a method for coating, packaging and/or otherwise treating solid and liquid materials to facilitate their handling in an aqueous medium.

It is another object of this invention to provide a method for coating, encasing, packaging and/or otherwise treating solids and liquids with water-soluble film-forming materials.

It is still another object of this invention to provide a method for coating or packaging solids and liquids with water-soluble film-forming polymers.

It is still another "further object of the present invention to provide treated solids and liquids to facilitate their handling for use in an aqueous medium.

It is a further object of this invention to provide protectively coated solids.

It is still another object of the present invention to provide a packaged solid or liquid which is adapted for use in aqueous systems whereby the package dissolves in said aqueous medium to dispense the said solid or liquid.

"ice

Other objects will appear hereinafter as the description proceeds.

It has been discovered that N-alkoxymethyl polypyrrolidone and N-alkthiomethyl polypyrrolidone in which from about 14% to about 22% of the amide nitrogen 'atoms are substituted by N-alkoxymethyl or N-alkthiomethyl groups, respectively, are admirably suited for the purposes and ends above described, and that such polymers are far superior to all others for such purposes as packaging and the like having the optimum in the necessary and desired characteristics listed above.

The N-alkoxymethy-l polypyrrolidones differ markedly from the N-alkoxymethyl derivatives of nylon 6, nylon 6-6, and nylon 6-10 in that they are water soluble while the nylon based compounds are not. In addition the N-alkoxymethyl polypyrrolidones exhibit advantages over other polymers suitable for water-soluble films or coatings such as polyvinyl alcohol, ethoxylated polyvinyl alcohol, the alkyl celluloses, the hydroxyalkyl celluloses, gelatin, and starch. In most cases these polymers must be external-1y plasticized by addition of watersoluble compounds such as glycerin in order to obtain satisfactory properties. The water-soluble plasticizer tends to migrate and also increase sensitivity to water vapor and in time moisture pick-up becomes so great that the film or coating fails as a protective barrier. The 'N-alkoxymethyl polypyrrolidones are internally plasticized with no migration possible and moisture sensitivity can be regulated by the percent of nitrogen substitution. 'Ethoxylated polyvinyl alcohol and polyvinyl alcohol are very slowly soluble in water at or below 77 F.; methyl cellulose shows greater rate of solution in cold water than in hot; the N-alkoxymethyl polyrrolidones have a high rate of solution in either cold or hot water. Films cast from N-alkoxymethyl polypyrrolidones within the useful range of nitrogen substitution have physical strength properties comparable to polyvinyl alcohol or ethoxylated polyvinyl alcohol films, and far higher elongation than that reported for methyl cellulose film. The N-alkoxymethyl polypyrrolidone films are less affected by relative humidities over 50% than polyvinyl alcohol or ethoxylated polyvinyl alcohol film-s and exhibit less embrittlementat low temperatures. The rate of solution of polyvinyl alcohol and ethoxylated polyvinyl alcohol films in water decreases drastically at pH '8 or higher; the N-alkoxymethyl polypyrrolidone films do not show any change in rate of solution with change in pH. Polyvinyl alcohol and ethoxylated polyvinyl alcohol water solutions have higher viscosities than equivalent concentration solutions of N-alkoxymethyl polypyrrolidones. Polyvinyl alcohol and ethoxylate polyvinyl alcohol can not be heated above 200 F., because of crosslinking at higher temperatures. N-alkoxymethyl polypyrrolidone can be heated to C. without materially aifecting properties.

What has been stated above with respect to the N-alkoxymethyl poly'pyrrolidones applies to the N-alkthiomethyl polypyrrolidones, too, of course.

The compounds which are contemplated for use in the present invention are derived from polypyrrolidone by the substitution of from about 14% to about 22% of the amide nitrogen atoms by a group of the formula-:-

wherein A is oxygen or sulfur and R is methyl or ethyl.

The general method for the preparation of such derivatives is fully described in copending application Serial No. 853,693, filed Nov. 18, 1959, now abandoned and the disclosure of that application relating to the compounds herein contemplated and the methods for making same is hereby incorporated by reference thereto.

While the immediate and most advantageous use of the compounds with which this invention is concerned lies in the packaging of detergents and similar products, it is equally clear that protective coatings of a temporary nature may be applied to any solid or used to encapsulate any liquid in any of the well-known and conventional methods. Thus a solution of the polymer may be applied directly to an article, material, compound or the like by brushing, dipping, spraying, roller coating, etc., followed by a conventional air drying or baking to remove the solvent. Alternatively, unsupported films of the polymer may be prepared, again, in the conventional ways for so doing, which films can be sealed by heat, solvent, adhesive or the like to form packages in which the aforementioned items are enclosed.

The following examples will serve to illustrate the present invention without being deemed limitative thereof. Parts are by weight unless otherwise indicated.

EXAMPLE 1 A 20% solution of N-methoxymethyl polypyrrolidone (prepared from polypyrrolidone having a relative viscosity of 2.5) and a nitrogen substitution of 14.5% is prepared in 50-50 water-methanol. The pH of the solution is 7.71 and the viscosity is 240 cps. Films are then cast from this freshly made solution on Mylar covered glass plates and (1) baked at 140 C. for 20 minutes and (2) air dried. The films are then conditioned at 20% relative humidity and 77 F. for 2, 14 and 28 days and tensile Percent N substitution of polymer:

4 EXAMPLE 3 Films are cast as in above examples from 20% by weight solutions in 50/50 methanol-water, baked for 20 minutes at 140 C. and conditioned for 2 .days at 50% relative humidity and 77 F. 'Elmendorf tear strength is determined. The polypyrrolidone used has a relative viscosity of 2.5.

Tear strength g. /m11) EXAMPLE 4 Films are prepared of 1.7-2.0 mils thickness from solu- 20 tions containing 20% by weight of N-methoxymethyl polypyrrolidone having nitrogen substitutions of 14.5. and 15% and compared with similar films from solutions of ethoxylated polyvinyl alcohol for blocking characteristics by placing two pieces of each film faceto face subjected to a weight of 500 g./sq. in. in and 98% relative humidity atmospheres. After 24 hours the films are peeled apart and any blocking is noted. The visual appearance of the films is also noted.

Relative Polymer Humidity, Blocking Visual Appearance Percent 75 Very slight-.. Soft, tender, no wrinkling. 75 do Do. 75 Severe Soft, tender, wrinkled.

98 Slight Soft, tender, some wrinkling. b 98 do Do. Ethoxylated polyvinyl 98 Complete"--. Film going into solution.

alcohol.

strength and elongation are measured employing a cross- EXAMPLE 5 head speed of 20 inches per minute on an Instron tester. Similiar films are made and conditioned from similar solutions which have been aged for 26 days. The results appear in Table I.

l-inch x 2-inch'strips of films 1.7-1.9 mils thick from 45 solutions of (A) 14.5% nitrogen substituted polymer,

(B) 21.8% nitrogen substituted,-and (C) ethoxylated Table I 2 Day Conditioned 14 Day Conditioned 28 Day Conditioned Film-drying Condi- Solution tions p Tensile Percent Tensile Percent Tensile Percent (p.s.i.) Elong. (p.s.i.) Elong. (p.s.i.) Elong.

Fresh Air 4, 390 28s. 5 3, 970 260.5 4,850 321 D0 140 O.20 mm"--- 3, 310 56 3, 390 188. 5 3, 270 212. 5 Aged Air 4,420 271 4,150 222 4,930 293 D0- 140 C.20 min---" 3, 790 251. 5 4, 490 215 4, 020 261. 5

EXAMPLE 2 d polyvinyl alcohol are added to ml. portions of water Example 1 is repeated except that the percent nitrogen substitution is 21.8%. This polymer is made up to a 20.8% solution and has a pH of 7.65 and a viscosity of buffered to pHs of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. The.

speed with which the film is attacked, time to effect com-' plete solution or disintegration and presence of residue 297 cps. Results appear in Table II. is noted. The results appear below in Table IH. 1

Table II 2 Day Conditioned 14 Day Conditioned 28 Day Conditioned Film-drying Condi- Solution tions I I Tensile Percent Tensile Percent Tensile Percent (p.s.i.) Elong. (p.s.i.) Elong. (p.s.i.) Elong.

Fresh Air 3,020 391.5 2,530 293 2,910 389.5

D0- C.20 min 3, 270 379. 5 3, 760 395 2, 327 Aged Air 2,830 320 3,090 226 3,080 346 Do-- 140 C.20 min 3, 370 358. 5 2, 540 211 2, 890 386 5 6 Table III C above by heat sealing along three edges, filling the packages with detergent and finally heat sealing the fourth Polymer pH Speed of Tim o m- Residue edge. The heat sealing is done with a Sealine hand sealer Attack y pla 50111-01r which consists of an electrically heated Teflon coated Water Dlsmteg'(sec') 5 metal wheel with corrugated A; inch wide rim axially 1 Immediate 2O Slight mounted for tree rotation. The detergent used is of 2 25 E, the following composition: 2 i g8 Percent 5 18 D: Sodium dodecyl benzene sulfonate 34 g g 133: 10 Sodium tripolyphosphate 40 8 20 D Sodium s1l1cate 7 3 12 g; Sodium carboxy methyl cellulose 0.5 1 10 None, Optical 'brighteners 0.07 g g3: Sodium sulphate Bal. 4 11 Do. 15 11 Do. Each package is prepared containing g. of above deg g 53' tergent composition. The packages are placed in 500 s 12 Do: ml. of water at 70 F. Packages made of polymers A 8 8 3: and B release the contents within 15 seconds. Packages 1 120 D0. of polymer C require 10 minutes for such release. 2 147 150. i g3: EXAMPLE 8 g D3: Polymer A and polymer C as packages for 120 g. of g (I) 165 g but the above described detergent are tested for soil redeposiintact. tion and cleaning properties for a laundering cycle. 3 B3: For each run 2. Dexter top loading washing machine is filled with 10 gallons of water at 120 F. and 130 grams of ,Mhoum screened hoteldvacuum cleaner dust added. Then 1(Either 120 grams of etergent, 120 grams of detergent pac aged f the i i S It Is fqmte evlilentt z in polymer fihn A, or 120 grams of detergent packaged in 0 1 P 1 fi supgngr p sg g polymer film C is added and agitation carried out for 1 fig g g g iz 0 an especla y so un er s 1 y minute. (Both film packages are of equivalent size and EXAMPLE 6 film thickness.) 20 pieces of 36 in. clean, dry cotton sheeting 3 pieces of 8 in. x 8 in. Indianhead cloth, and In this example the low temperature properties of the 4 1 /2 in. x 4 in. swatches of each of the following standinstant compositions are compared with ethoxylated polyard materials-American Conditioning House, Standard vinyl alcohol (C). The 14.5% nitrogen substituted poly- U.S. Testing, and Test fabric-are added. The full load mer (A) and the 21.8% nitrogen substituted polymer is agitated. for 20 minutes. The standard soiled materials (-B) of Example 5 are used again. 1.7 to 1.9 mil thick and Indianhead cloth swatches are removed, wrung dry film are conditioned at 0 C. and -78.5 C. and are then 40 by hand, rinsed in 1 liter of water at 100 F. for 5 minsubjected to a rapid crumpling stress at these temperautes, wrung dry by hand, and dried on an aluminum plate tures. The conditioning is carried out by immersing a heated by a steam bath. sealed glass jar containing the film for 3 hours in either A model 610 Photovolt Corp. photometer with a trian ice-water bath (0 C.) or crushed Dry Ice (-78.5 timulus green filter on the search is calibrated to give a C.). The results are given in Table IV. reading of 86 with a standard white ceramic plate. The

Table IV reflectances of each piece of the soiled materials and Indianhead cloth are determined on a gray cardboard back- 0. ground. In all cases reflectances are taken using uni form thicknesses of cloth. The indivdual readings for Fnm intact each type of soiled material are averaged and an overall Do. average of the three types of soiled material obtained. Fllm breaks pleces- Cleaning power is reported as this overall average and soil redeposition as the average of the Indianhead cloth EXAMPLE 7 readings. The higher the value, the greater the cleaning Detergent packages are prepared from two thicknesses power and the less soil redeposition. The results are as (each 1.7-2.0 mils) of films from polymers A, B and follows:

DETERGENT (N0 PACKAGE) Cleaning Soil Re- Test Swatch Readings Average Power deposition alue 45 47 47 48 46.75 45 46 45 42 44.5 44.16 42 42 42 a9 41. 25 79.3 so 79.4 79.52 79.52

DETERGENT PACKAGED IN POLYMER F-ILM A Cleaning Soil Re- Test Swatch Readings Average Power deposition Value American C0nd.House 44 46 45 44 44.75 Test fabric 39 42 3s 39 39.5 420 Stand. U.S. Testin 43 41 40 43 41.75 Indianhead cloth 78 78.1 78.3 78.11 78.11

a,277,oo9

DETERGENT IN POLYMER FILM C Cleaning Soil Re- Test Swatch Readings Average Power deposition Value American Cond. House 44 44 43 44 43.75 Test fabric 38 34 36 38 37. 75 40.5 Standard U.S.Testmg 41 40 41 38 40.0 Indianhead cloth 77.3 77.1 76.4 76.91 76.91

From the above data it is evident that in addition to EXAMPLE 14 superior dissolution characteristics as well as outstandingly better physical properties described above, better cleaning and redeposition characteristics are obtained with the instant pacakges as compared to packaging with ethoxylated polyvinyl alcohol.

EXAMPLE 9 EXAMPLE 10 A 20% by weight solution of 14.5% nitrogen substituted product (Polymer A) in 50/50 by Weight mixture of methanol and water is prepared. Paper is coated by a roller coating technique to give a film on one side of the paper. After, drying, the coated paper shows excellent grease and oil resistance and imperviousness.

EXAMPLE 1 l A package of polymer A is prepared as above containing cottonseed oil. There is no evidence of oil loss or permeability after 90 days storage at 100 F.

EXAMPLE 12 Examples 8-11 are repeated employing N-methoxy methyl polypyrrolidone with the following nitrogen substitution values.

A. 15% D. B. 17% E. 21.8% C. 18.8% F. 22%

Excellent results are obtained in each instance.

EXAMPLE 13 Example 12 is repeated employing the following polypyrrolidone derivatives:

. N-meththiomethyl-l4% nitrogen substitution N-meththiomethyl16% nitrogen substitution N-meththiomethyl22% nitrogen substitution N-ethoxymethyll4.2% nitrogen substitution N-ethoxymethy121.6% nitrogen substitution N-eththiomethyl-15% nitrogen substitution N-eththiomethyl21% nitrogen substitution Similar excellent results are obtained as in the previous examples. The polypyrrolidone employed to prepare the derivatives described in Examples 4-13 has a relative vis-. cosity of 2.5.

Examples 7 through 13 are repeated employing polypyrrolidones of the following viscosity grades:

A. 1.5 F. 10.0 B. 2.2 G. 12.5 C. 2.3 H. 22.5 D. 3.0 I. 25.0 E. 5.0

The polypyrrolidones used in the preparation of the derivatives herein described as set forth in copending application Serial No. 853,693 mentioned above may be of any viscosity grade and suitably between 1.5 and 25 (rela-1 tive viscosity--measured as a 1% solutionvin m-cresol).:

Other variations in and modifications of the described processes which will be obvious to those skilled in the art" can be made in this invention without departing from the scope or spirit thereof.

We claim:

1. In a method for packaging substantially water-free solids and liquids in a solid, film-forming material, the

improvement which comprises employing as the film-f0rming material polypyrrolidone containing from about 14% to about22% substitution of the nitrogen atoms bya group of the formula CH AR wherein A is selected from the group consisting of exygen and sulphur and R is selected from the group consisting of methyl and ethyl.

2. A method as defined in claim 1 wherein A is oxygen and R is methyl.

3. A method as defined in claim 1 wherein A is oxygen and R is ethyl.

4. A method as defined in claim 1 wherein A is sulphur and R is methyl.

5. A method as defined in claim 1 wherein A is sulphur and R is ethyl.

6. In a method for packaging a solid detergent composition substantially free of water in an:envelope,. the

improvement which comprises employing as the envelope. 1

a water-soluble polypyrrolidone derivative, said derivative containing from about 14% to about 22% of the nitrogen atoms of the polypyrrolidone substituted with a substituent selected from the group consisting of methoxymethyl, ethoxymethyl, methiomethyl and ethiomethyl.

7. In a method as defined in claim 6 wherein the sub-1 stituent on the polypyrrolidone is methoxy methyl.

8. In a method as defined in claim 6 wherein the substituent on the polypyrrolidone is ethoxy methyl.

9. In a method as defined in claim 6 wherein the sub.- stituent on the polypyrrolidone is methiomethyl.

10. In a method as defined in claim 6 wherein the substituent on the polypyrrolidone is ethiomethyl.

11. A method for packaging substantially water-free 1 solids and liquidmaterials which comprises enveloping said material with a polypyrrolidone film-forming deriva-.

tive, saidderivative containing from about 14% to about 22% of the nitrogen atoms of the polypyrrolidone substituted with a substituent selected from the group consisting of methoxymethyl, ethoxyrnethyl, methiomethyl, and ethiomethyl.

12. A method as defined in claim 11 wherein the polypyrrolidone contains about 21.8% of the nitrogen atoms substituted with methoxy methyl groups.

13. A method as defined in claim 11 wherein the polypyrolidone contains about 21.8% of the nitrogen atoms substituted with methoxy methyl groups.

14. A method for producing a water-removable, grease and oil resistant coating on a base which comprises applying to said base an aqueous solution of polypyrrolidone containing from about 14% to about 22% of the nitrogen atoms substituted with a grouping selected from the group consisting of methoxymethyl, ethoxymethyl, methimethyl and ethiomethyl groupings and drying the coating.

15. A method as defined in claim 14 wherein the base is a paper base.

16. A method as defined in claim 15 wherein the grouping is methoxymethyl.

17. A package consisting essentially of a water-free detergent material in an envelope of a water-soluble polypyrrolidone derivative, said derivative containing from about 14% to about 22% of the nitrogen atoms substituted with a grouping selected from the group consisting of methoxymethyl, ethoxymethyl, methiomethyl and ethiomethyl groupings.

18. A package as defined in claim 17 wherein the envelope is polypyrrolidone and the substituent grouping is methox ymethyl.

References Cited by the Examiner UNITED STATES PATENTS 1,780,375 11/1930 Bradley 117155 2,086,903 7/1937 Ellis 117--155 2,734,004 2/1956 Robinson 117-1395 3,000,830 9/1961 Fong et al. 252117 3,055,834 9/1962 Charle et al. 252 3,061,549 10/1962 Dickey 252-90 3,113,674 12/1963 Kiefer et a1. 252--90 XR FOREIGN PATENTS 451,839 10/ 1948 Canada.

OTHER REFERENCES Carns et al.: Preparation and Properties of N-Methylol, N-Alkoxymethyl and N-Alkylthiomethyl Polyamides, pp. 651-657 relied on, vol. 71, Journal of American Chem. Society (1949).

Haas et al.: Hydroxyethyl Nylon, Journal of Polymer Science, vol. 15 (1955), pp. 427429 and 437-443.

LEON D. ROSDOL, Primary Examiner. JULIUS GREENWALD, Examiner.

A. T. MEYERS, W. E. SCHULZ, Assistant Examiners. 

14. A METHOD FOR PRODUCING A WATER-REMOVABLE GREASE AND OIL RESISTANT COATING ON A BASE WHICH COMPRISES APPLYING TO SAID BASE AN AQUEOUS SOLUTION OF POLYRROLIDONE CONTAINING FROM ABOUT 14% TO ABOUT 22% OF THE NITROGEN ATOMS SUBSTITUTED WITH A GROUPING SELECTED FRM THE GROUP CONSISTING OF METHOXYMETHYL, ETHOXYMETHYL, METHIOMETHYL AND ETHIOMETHYL GROUPINGS AND DRYING THE COATING. 